Be careful with MFP calorie estimates - don't work for everyone

unknown

My goal is to maintain my weight. If I eat according to MFP, I gain weight. If I eat according to My Tracks, I maintain.
MFP or MapMyRide consistently estimate my calories burned during a bike ride by 200% to 350%.
For example, I rode 41 minutes today, 16-20 mph, and MFP imported from MapMyRide that I burned 632 calories; MyTracks estimated my calories as 186. Both apps use the GPS in my smartphone, track the same distance, same time, and same speed.
Another day I rode 21 miles in 98 minutes, averaging 12.9 mph. MFP estimates my calorie consumption at 955, while My Tracks reports 403.
Another day I rode 21 miles in 120 minutes, averaging 10.5 mph. MFP estimates my calorie consumption at 877, while My Tracks reports 420.

unknown

My weight loss on MFP was predictable and as I expected when I cut the MFP calorie burn numbers in half.